“Live each day as if it were your last.” This advice has never made much sense to me. If I assume that today is my last, do I put money in savings? Do I get a good night’s sleep? Exercise? Refrain from the eating a third Little Debbie Oatmeal Cream Pie?

In some ways, life would be much easier if you knew that today was your last day on Earth. I am not saying it wouldn’t be sad, it’s just that the knowledge that it was your last day could provide some real clarity about what is most important and what is a waste of time.

While getting a cancer diagnosis twice in my life was not pleasant, it really helped create clarity and focus on what mattered most to me. In my case, it was love, kindness, and family. Unquestionably. A real challenge is keeping this focus and clarity when the treatment is successful and life returns to “normal.”

At the crux of the human condition is that today may or may not be your last day. What the heck do you do with that? Death is a certainty, but the timing is not. This combination creates a fundamental uncertainty in life.

In mathematics, there is a way of working with complex systems that is known as constrained optimization. The idea is that there are constraints – boundary conditions – in any situation. The goal is to optimize the outcome you seek within the constraints of the system. To me, this is life in a nutshell. How do you optimize your life within the reality that today may or may not be your last?

I think the secret is treating your life as practice – letting go of the idea that you will ever get somewhere. Maybe you have 10 minutes or maybe you have 10 decades, but either way, you just keep practicing until you are interrupted by death. There is no pot at the end of the rainbow, there is only the rainbow – the arc of your life.

This all begs the question, “What do we practice?” Based on three decades of research in human development and wellbeing, I believe that the following are the four pillars of good life practice:

Presence: awareness, acceptance, clarity

Positivity: gratitude, compassion, curiosity, awe.

Purpose: values, commitments, choice, responsibility

Connection: listening, communication, service

We can set aside time at the start and end of our day to practice these things. We can practice these things throughout the day in our work, at home, and when we are out in the world. Presence, positivity, purpose, and connection may seem like abstract things to practice, but we can make them as concrete and intentional as practicing the piano or tennis.

If we practice these things daily, then life ends up being chock full of rich experience. On the other hand, if we practice waiting for the day when everything is the way we want it to be, then our last day on Earth will be filled with waiting. This is your life — what are you practicing right now?